1. Field of the Invention
This invention relates to a method and apparatus employed in a double chainstitch machine used for bottom hemming of a T-shirt, etc., a lock stitch machine or the like, to control the fabric edge position in order to form a seam on a sewn product at a constant distance from a fabric edge.
2. Description of the Related Art
In bottom hemming of a T-shirt, or the like, by utilizing a double chainstitch machine or a lock stitch machine, a missing stitch or far stitch may happen when sewing the T-shirt at an inwardly folded back bottom. In order to prevent the degradation in quality of sewn products due to such a missing stitch or far stitch, the sewing width must be maintained constant to form the seam at a constant distance from the bottom.
Conventionally, in order to appropriately feed the fabric portion where no missing stitch or far stitch is to be produced to the needle location, an operator manually controls the position of a T-shirt fabric, with a folded back bottom, by shifting the fabric to the position where the fabric is able to obtain a fixed sewing width after inserting the fabric beneath the presser foot and puller.
As mentioned above, there are problems associated with the conventional manual positioning of fabric, including that those conventional methods require much labor, thereby lowering the sewing efficiency. Also, the conventional method require the skill of an operator in positioning the fabric thus preventing sewing automation.